1. Field of the Invention
The present invention relates to novel methylenically-substituted undecadiene, and to a novel process for the preparation thereof. By "methylenically-substituted" as utilized herein, there are intended not only methylene, .dbd.CH.sub.2, derivatives, per se, but also derivatives of the type, .dbd.CHR and .dbd.CRR, wherein R is lower alkyl.
2. Description of the Prior Art
The addition of conjugated dienes to straight chain dimers of butadiene is a known reaction. French Pat. No. 2,077,072 discloses such an addition reaction and, in particular, features the reaction between a 1,3 conjugated diene having the structural formula: ##STR4## and a substituted butadiene dimer having the structural formula: ##STR5## wherein R.sub.a and R.sub.c are selected from the group consisting of hydrogen and lower alkyl, R.sub.b is selected from the group consisting of hydrogen, lower alkyl and lower alkenyl, and X is selected from the group consisting of lower acyloxy, aryloxy having from 6 to 14 carbon atoms, lower alkoxy and hydroxy.
The aforementioned French patent discloses that the reaction produces two compounds, one having a straight chain structure wherein the carbon atom in the 8 position of the 1-substituted alkadiene is linked with the terminal carbon atom of the 1,3 conjugated diene, and the other having a structure wherein the 2-carbon atom of the 1-substituted alkadiene is linked with the terminal carbon atom of the 1,3 conjugated diene. An example given in the patent involves the reaction between 1,3 butadiene having the structural formula: ##STR6## and 1-acetoxy-2,7-octadiene having the formula: ##STR7## to prepare an 8-substituted derivative having the structural formula: ##STR8## and its 2-substituted isomers having the structural formulas: ##STR9##
The French patent also discloses that the production of the 8-substituted derivative is favored when the addition takes place in the presence of a trivalent phosphorus compound such as triphenylphosphine, tri-n-butylphosphine, tri-isopropylphosphine, tricyclohexylphosphine, phenyldichlorophosphine, phosphorus trichloride and triphenylphosphate. According to the examples given in the French patent, the atomic ratio of the trivalent phosphorus to rhodium present is less than or equal to 1.